This invention relates to fluid power devices, and more particularly it is concerned with compressible fluid engines that operate with an oscillating rotary motion.
The fluid device of this invention is an improvement of the oscillating engine disclosed in my prior U.S. Pat. No. 3,181,513 issued on May 4, 1965, and the disclosure of that patent is expressively incorporated by reference in this specification. As fully described in my U.S. Pat. No. 3,181,513, the oscillating engine of that invention comprises a pair of adjacent arcuate chambers, in each of which a vaned rotor is mounted to move in an oscillating manner. The two rotors are synchronized through a gear train to oscillate in opposite directions, and separate valve means are provided for controlling the flow of fluid into and out of the chambers in timed relation with the oscillating motion of the rotors.
In the internal combustion engine embodiment disclosed in my U.S. Pat. No. 3,181,513, a rotary exhaust valve and a poppet-type intake valve for each chamber are actuated through pushrods by a cam on each respective rotor shaft. The exhaust and intake openings to each chamber are located in the intermediate portion of the chamber, between the extreme positions of the rotor. In particular, the exhaust opening is at approximately the midpoint of rotor oscillation, and the intake opening is adjacent to the exhaust opening but displaced toward the expansion position of the rotor in each chamber.
The engine operates on a modified two-stroke cycle, with initial compression of the combustible mixture occurring on the back side of the rotor during the power stroke and the compressed charge being introduced to the combustion chamber midway during the return stroke. The intermediate arrangement of the exhaust and intake openings has been found to provide less than optimum overall engine efficiency, and the pushrod valve actuating mechanism of the disclosed embodiment has drawbacks from the standpoints of performance and dependability. In addition, the rotary exhaust valve design of the disclosed embodiment does not include positive control for fully opening the valve but depends upon flow of the exhaust gases through the valve when it starts to open to rotate it to the fully open position.